My SD Card reader reads an older 512 MB card, but fails with two larger cards: a Verbatim 8Gb and Dane-Elec 16Gb cards--both class 4. These are the only ones I have to try at the moment.

BOTH large cards work fine in my Acer Aspire One Netbook, and in my Gateway NX860XL laptop which have 2.6 kernels.
In fact both cards are listed as working SD cards in http://elinux.org/RPi_VerifiedPeripherals

dmesg fills completely with errors as shown below...

I looked for patches or bugs, but came up empty.
Any ideas or other places I should post this issue?

If you still have a Windows install on that system, I'd suggest to test the card reader and sdhc card using that. In general many card readers, and especially the ones you're dealing with, are often of rather bad and unreliable quality, sometimes even up to the point of phyiscally harming your media…

While not very convenient, using an external USB card reader often offers better quality and driver support than some of the internal ones.

[1] I've had lots of 'fun' with this one "SD Host controller [0805]: JMicron Technology Corp. Standard SD Host Controller [197b:2381]"; unfortunately I wouldn't expect this to improve. Given existing reports about these devices and my own experiences, I'm not convinced that these problems could be fixed from the driver side and aren't design errors in the hardware.